We revisit the merger rate for Galactic double neutron star (DNS) systems in light of recent observational insight into the longitudinal and latitudinal beam shape of the relativistic DNS PSR J1906 + 0746. Due to its young age and its relativistic orbit, the pulsar contributes significantly to the estimate of the joint Galactic merger rate. We follow previous analyses by modelling the underlying pulsar population of nine merging DNS systems and study the impact and resulting uncertainties when replacing simplifying assumptions made in the past with actual knowledge of the beam shape, its extent, and the viewing geometry. We find that the individual contribution of PSR J1906 + 0746 increases to $\mathcal {R} = 6^{+28}_{-5} \, \mathrm{Myr}^{-1}$ although the values are still consistent with previous estimates, given the uncertainties. We also compute contributions to the merger rates from the other DNS systems by applying a generic beam shape derived from that of PSR J1906 + 0746, evaluating the impact of previous assumptions. We derive a joint Galactic DNS merger rate of $\mathcal {R}^{\mathrm{gen}}_{\mathrm{MW}} = 32^{+19}_{-9}\, \mathrm{Myr}^{-1}$, leading to a LIGO detection rate of $\mathcal {R}^{\mathrm{gen}}_{\mathrm{LIGO}} = 3.5^{+2.1}_{-1.0}\, \mathrm{yr}^{-1}$ (90 per cent conf. limit), considering the upcoming O3 sensitivity of LIGO. As these values are in good agreement with previous estimates, we conclude that the method of estimating the DNS merger and LIGO detection rates via the study of the radio pulsar DNS population is less prone to systematic uncertainties than previously thought.

中文翻译：

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重新审视银河双中子星合并和 LIGO 探测率

根据最近对相对论 DNS PSR J1906 + 0746 的纵向和纬度光束形状的观测洞察，我们重新审视了银河双中子星 (DNS) 系统的合并率。由于它的年轻和相对论轨道，脉冲星做出了重大贡献对联合银河合并率的估计。我们通过对九个合并 DNS 系统的潜在脉冲星群进行建模来遵循先前的分析，并研究在用对光束形状、其范围和观察几何形状的实际知识替换过去所做的简化假设时的影响和由此产生的不确定性。我们发现 PSR J1906 + 0746 的个人贡献增加到 $\mathcal {R} = 6^{+28}_{-5} \, \mathrm{Myr}^{-1}$ 尽管值仍然一致考虑到不确定性，与之前的估计一样。我们还通过应用源自 PSR J1906 + 0746 的通用波束形状来计算其他 DNS 系统对合并率的贡献，评估先前假设的影响。我们推导出联合银河 DNS 合并率 $\mathcal {R}^{\mathrm{gen}}_{\mathrm{MW}} = 32^{+19}_{-9}\, \mathrm{Myr} ^{-1}$，导致 LIGO 检测率为 $\mathcal {R}^{\mathrm{gen}}_{\mathrm{LIGO}} = 3.5^{+2.1}_{-1.0}\， \mathrm{yr}^{-1}$（90% conf. limit），考虑到即将到来的 LIGO 对 O3 的敏感性。由于这些值与之前的估计值非常一致，我们得出结论，通过无线电脉冲星 DNS 种群的研究来估计 DNS 合并和 LIGO 检测率的方法比以前认为的更不容易出现系统不确定性。